//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
const ll mod=998244353;
ll fact[1001000],rfact[1001000];
ll C(int n,int k)
{
	if(k<0||k>n) return 0;
	return fact[n]*rfact[k]%mod*rfact[n-k]%mod;
}
ll ksm(ll a,ll b)
{
	ll ans=1;
	while(b)
	{
		if(b&1) ans=ans*a%mod;
		b>>=1;
		a=a*a%mod;
	}
	return ans;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	fact[0]=1;
	rfact[0]=rfact[1]=1;
	for(int i=1;i<1001000;i++) fact[i]=fact[i-1]*i%mod;
	for(int i=2;i<1001000;i++) rfact[i]=(mod-mod/i)*rfact[mod%i]%mod;
	for(int i=2;i<1001000;i++) rfact[i]=rfact[i]*rfact[i-1]%mod;
	int e,p,w,t;
	cin>>e>>p>>w>>t;
	int n=e+p+w;
	ll ans=0;
	for(int v=t+1;v<=n+t;v++)
	{
		ll f=1,g=0;
		if(v-t-p+1>=1)
		{
			f=ksm(n-v+t,p);
			g=ksm(n-v+t+1,p);
			g=(g+mod-f)%mod;
		}
		else
		{
			int bound=v-t;
			f=ksm(n-v+t,bound)*fact[n-bound]%mod*rfact[n-p]%mod;
			g=ksm(n-v+t+1,bound)*fact[n-bound]%mod*rfact[n-p]%mod;
			g=(g+mod-f)%mod;
		}
		ll f2=1,g2=0;
		if(n-min(n,v)<e)
			f2=g2=0;
		if(v-t-p+1>=1)
		{
			f2=ksm(n-v+t-e,p);
			g2=ksm(n-v+t+1-e,p);
			g2=(g2+mod-f2)%mod;
		}
		else
		{
			int bound=v-t;
			f2=ksm(n-v+t-e,bound)*fact[n-bound-e]%mod*rfact[n-p-e]%mod;
			g2=ksm(n-v+t+1-e,bound)*fact[n-bound-e]%mod*rfact[n-p-e]%mod;
			g2=(g2+mod-f2)%mod;
		}
		ll tot=(g*C(e+w,e)-g2*C(n-min(n,v),e)%mod)%mod;
		ans=(ans+tot)%mod;
	}
	ll all=C(e+p+w,e)*C(p+w,p)%mod*fact[p]%mod;
	cout<<ans*ksm(all,mod-2)%mod<<'\n';
	return 0;
}